THE RELATIONSHIPS BETWEEN THE OPERATIONAL CONDITIONS AND MIXING BEHAVIOUR IN THE METHANE-CIRCULATION ANAEROBIC GAS-LIFT BIOREACTOR

Abstract

In this paper the mixing characteristics and their influencing elements in a gas-lift bioreactor with bio-gas circulation were analysed by means of tracer test. The results showed that the sludge concentration in the reactor influenced the mixing state for the bypass and the deadspace increased with increasing of the sludge concentration. The volume utilizing efficiency (η_v) of reactor decreased from 89.9% to 82. 5%, and the bypass rate (1-η_t) increased from 11.5% to 23.1%, when the sludge concentration increased from 14.6gl^-1 to 21.8gl^-1. Therefore it can be deducted that it is unilateral to increase simply the sludge concentration of reactor in an anaerobic contact process. The bypass is main factor for the decline of treatment efficiency of reactor.